Inliners International Forums General Discussion Hi Performance Nova project progress

I think moly rings are in fact cast iron, with a thin insert of molybdinum usually applied to the cast iron in the form of a plasma spray.

This quote - taken from the following website:

http://aapistons.com/index.php?main_page=page&id=2&chapter=10

6. Molybdenum (Moly) Ring-Cast iron ring which uses a Molybdenum alloy as a face material.